Fixed FormPathLeaves inference for arrays.

Author: ciscoheat

src/lib/stringPath.ts

@@ -122,14 +122,25 @@ type StringPath<
 												never,
 												T[K]
 											>
-										: If<
-												Options,
-												'filter',
-												'leaves' | 'all',
-												Concat<Options['path'], `${K}[${number}]`>,
-												never,
-												U
-											>)
+										: NonNullable<U> extends object
+											? IsAny<T[K]> extends true
+												? Concat<Options['path'], `${K}[${number}]`>
+												: If<
+														Options,
+														'filter',
+														'all',
+														Concat<Options['path'], `${K}[${number}]`>,
+														never,
+														U
+													>
+											: If<
+													Options,
+													'filter',
+													'leaves' | 'all',
+													Concat<Options['path'], `${K}[${number}]`>,
+													never,
+													U
+												>)
 								| (NonNullable<U> extends object
 										? StringPath<
 												NonNullable<U>,

src/tests/legacy/paths.test-d.ts

@@ -327,11 +327,7 @@ test('FormPath with type narrowing, arrays', () => {
 test('FormPath with type narrowing, union', () => {
 	type NameArrays = FormPath<Obj, string | number>;
 
-	const t1: NameArrays = 'name';
-	const t2: NameArrays = 'points';
-	const t3: NameArrays = 'tags[3].name';
-	const t4: NameArrays = 'names[3]';
-	const t5: NameArrays = 'tags[0].parents[5]';
+	const ok: NameArrays[] = ['name', 'points', 'tags[3].name', 'names[3]', 'tags[0].parents[5]'];
 
 	// @ts-expect-error incorrect path
 	const i1: NameArrays = 'tags';
@@ -371,7 +367,6 @@ test('FormPath with any type', () => {
 
 	// @ts-expect-error Invalid path
 	const f1: FP = 'nope';
-	// @ts-expect-error Invalid path
 	const f2: FPA = 'age[3]';
 });
 
@@ -389,6 +384,23 @@ test('Schemas with built-in objects', () => {
 	const tf: FPL = 'name';
 });
 
+test('Schema with nested arrays', () => {
+	const reportSchema = z.object({
+		reportDate: z.date(),
+		images: z.instanceof(File, { message: 'Please upload a file.' }).array()
+	});
+
+	const schema = z.object({
+		reports: z.array(reportSchema).min(1, 'At least one report must be submitted')
+	});
+
+	type FPL = FormPathLeaves<Infer<typeof schema>>;
+
+	const ok: FPL[] = ['reports[3].reportDate', 'reports[3].images[2]'];
+	// @ts-expect-error Invalid type
+	const no: FPL = 'reports[3]';
+});
+
 ///////////////////////////////////////////////////
 
 // Recursive schema test